THE lack of spring rain for the majority of Western Australia has resulted in most crops being unable to fill the excellent potential shown earlier in the season, according to the Grains Industry Association of WA's (GIWA) October Crop Report.
The report, released last Friday, said the slide in potential grain yield had been substantial over the past month with even the high rainfall regions going backwards.
Crop report author Michael Lamond said coolish September conditions helped arrest some of the slide in yield.
"However there simply has not been enough retained sub-soil moisture or rain during the year for crops to perform without spring rain," Mr Lamond said.
"In saying this, close inspection of cereal crops is indicating that most will yield more than expected and in select specific locations cereal crops will perform way above average."
It is not yet possible to make a call on grain quality, although there are expectations of high screenings in barley and less so in wheat.
Cool spring conditions appeared to have allowed wheat crops preferentially to fill the bottom half of heads due to the 'slow' burn off, rather than a 'quick' burn off from heat where all grains in the heads tend to pinch up and result in high screenings.
Mr Lamond said that lupin crops had grown exceptionally well and most would yield above average.
"Expectations are that canola crop quality will vary, even though the majority of canola plantings are in the medium to high rainfall areas, it is only in the southern and south western regions where above average yields are expected," he said.
"The increase in oat plantings this year is not going to result in excess supply as was anticipated earlier in the season.
"More oats than planned was cut for hay to hit tonnage targets as yields were down, while oats for grain is only expected to be average, except for the south west coastal regions."
Overall across WA there are some very poor areas and areas that usually contribute reasonable tonnages will be down, however the total slide in production will not be as dramatic as initially thought in September.
In the Geraldton zone, crops north of the Tenindewa line on the good sandplain are going to be average with small areas of the better managed country yielding above average.
"The west coastal regions in a line from Mingenew to Three Springs is good although grain yield potential drops away dramatically west of Carnamah and Coorow across to Eneabba," Mr Lamond said.
"The Chapman Valley has been in a sweet spot all year and there are some excellent wheat crops north and east of Geraldton.
"Crops fall away in the eastern areas on the heavier soils and some in the south eastern portions of the zone are going to be very poor."
The Kwinana North Midlands region has had a very low decile year for rain which has helped protect the crops in the west from leaching.
However, in the remainder of the zone, except for some strips that received summer rain, the crops have survived on small 'just in time' rainfall events throughout the season.
Some areas of the Kwinana South had up to 10 millimetres of rain in September and it is surprising what a difference that has made to the crops struggling for moisture.
The recent cool temperatures have been a saving grace and have allowed the wheat in particular to finish better than expected considering the growing season rainfall.
According to Mr Lamond, there will be areas in the Kwinana North East region that will be outstanding and others that will be terrible.
"Areas that received summer rain and had resulting stored moisture will be well above average," he said.
"Growers in a line from Kirwan bin to Koorda, Trayning, Nungarin, Merredin and down to Muntadgin will harvest above average crops.
"On the downside, the cut off in potential yields is pretty dramatic south west and north of this line that received the summer rain."
In Albany West, crops have hayed off very quickly which will take some of the top end grain yield potential from the better crops.
Most growers in the zone are expecting an above average year even with the lack of spring rain.
The crop outlook in Albany South was improving in the region as the season progressed from the scratchy start until recently when an unexpected frost has taken the top off many crops in the South Stirlings region.
"The 'freezing fog' as some have described it, has had a substantial impact on individual paddocks," Mr Lamond said.
"We estimate the reduction in total grain production from the frost event is likely to be less than five per cent."
The Lakes district will have a return to average yields for most areas in the region this year except for some very poor areas south and east of Lake Grace, and north east between Hyden and Lake Grace, particularly on the heavy country.
The Esperance zone will be well up on 2019's deliveries of less than 2mt.
"The contribution from the western areas from Lake King down to Ravensthorpe and a return to closer to average yields in the central portions of the zone will mean total production could be up by more than half a million tonnes," Mr Lamond said.
"The northern areas around Salmon Gums and north of Beaumont are going to be well below average due to a poor start and it being dry all year.
"The central Esperance zone had a very scratchy start although it has continued to improve with most areas receiving good falls of rain in August which has evened crops out."
Harvest has started across the grainbelt in the past couple of weeks, beginning with canola in the Geraldton and Esperance zone.
There has also been some early wheat and lupin crops in the north east of the State and early barley crops in the central and eastern areas.
With no rain forecast over the next few weeks, harvest will gear up in earnest with the next spell of warm weather.
